A secondary battery, which is easily applied to various product groups and has electrical characteristics such as high energy density, is universally applied not only for a portable device but also for an electric vehicle (EV) or a hybrid electric vehicles (HEV), an energy storage system or the like, which is driven by an electric driving source. The secondary battery is attracting attention as a new environment-friendly energy source for improving energy efficiency since it gives a primary advantage of reducing the use of fossil fuels and also does not generate by-products by the use of energy at all.
Secondary batteries widely used at the preset include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries and the like. An operating voltage of the unit secondary battery cell, namely a unit battery cell, is about 2.5V to 4.2V. Therefore, if a higher output voltage is required, a plurality of battery cells may be connected in series to configure a battery pack. In addition, depending on the charge/discharge capacity required for the battery pack, a plurality of battery cells may be connected in parallel to configure a battery pack. Thus, the number of battery cells included in the battery pack may be variously set according to the required output voltage or the demanded charge/discharge capacity.
Meanwhile, when a plurality of battery cells are connected in series or in parallel to configure a battery pack, it is common to configure a battery module composed of at least one battery cell first, and then configure a battery pack by using at least one battery module and adding other components. Here, depending on various voltage and capacity requirements, the battery pack including at least one battery module may be used for a home, or battery racks including at least one battery pack may be combined to configure a power storage device for industrial use.
The conventional battery pack includes at least one battery module, a pack case for packaging at least one battery module, and a BMS (Battery Management System) unit for controlling at least one battery module. Here, firmware update may be performed periodically or permanently at the BMS unit in order to improve the control performance of the battery pack.
In the conventional battery pack, when the firmware update is performed, a worker or the like firstly disassembles the pack case of the battery pack, and then a separate cable for updating is connected to the BMS unit. In other words, in this update method, the pack case of the battery pack should be dissembled whenever the firmware update is performed, and an additional cable connection should be performed for updating.
Accordingly, when the firmware update is performed, if the battery pack is used for home use, it is very difficult for a user or the like to perform the updating work alone, and thus the user is highly likely to depend on a professional worker or the like of an installation company at every updating.
Therefore, it is required to find a way to provide a battery pack that may improve the working efficiency and user convenience when firmware update is performed for a battery pack.